The exceptional urbanization, population growth, technological advancements recognized in all aspects of life in the 21st century present new challenges associated with the fast pace of modern life, in general with high impact related to transportation systems required for connecting people to economic/business opportunities, education, health services and the more.
The growth of population has increased dramatically the number of vehicles on the roads, resulting in high traffic capacity in cities and inter-cities, creating a growing and continuous need for improved and more effective transportation systems. Thus, the road junction becomes an essential component where its effectiveness, regarding transportation capacity, speed, space consumption and cost become more crucial to provide the necessary solution.
A full road interchange aims to provide a safe and smooth traffic flow between the various associated highway roads, passing through the road junction continuously. Junction may have limitations and drawbacks in three major aspects:                Area—requirement to use very large areas for building a full road interchange, mainly due to trapped spaces. Further, answering transportation regulations may not be feasible for interchanges having total area below 147,000 cubic meters (about 15 hectares). This issue is of particular importance in dense and highly populated areas.        Traffic—road design may particularly influence transportation capacity and driving speed and various other aspects of traffic flow, such as weaving (lane crossing) issues; sudden slowing down due to sharp curves and traffic ‘bottlenecks’; drop of traffic effectiveness when adding lanes in the same direction; problematic correction of navigation errors (such as performing an about-turn); and navigational complexities for the road user.        Cost—high cost may be associated with building of transportation-efficient interchanges (transition speed and traffic capacity); and, possibly further impact based upon the land value.        
Various road junctions are known and include for example, the “Continuous flow cloverleaf type interchange” of U.S. Pat. No. 4,861,184 to Mier et al., which describes a continuous flow cloverleaf type interchange for accommodating traffic from a plurality of road surfaces and the “Road junction” of U.S. Pat. No. 7,425,104 to Buteliauskas et al., which describes a road junction with roads arrayed in three, four or five different directions through the use of overpasses or tunnels in two levels.
Buteliauskas may provide an improved solution over Mier with regard to the construction area and construction cost. Buteliauskas road junction describes a technical design of high capacity two-level road interchange without intersecting traffic flows and only four small overpasses, in a four-way system for example, allowing for constant speeds to be maintained. Further, the road junction is designed to allow entry into the center area of the interchange, to turn around and exit in any desired direction, where area in the center of the junction becomes free for infrastructure and property development.
Buteliauskas's road junction (FIG. 2, U.S. Pat. No. 7,425,104) allows for most of the traffic to flow forward, depriving the interchange from having a main traffic direction, by transforming the straight main road into a curved road, thus imposing speed slowdown and reduced road capacity. Further, the left turn is diverging from the main traffic direction and the right turn diverges from the main road upstream and outside the junction center.
It is noted that Buteliauskas's road junction presents a further transportation failure: when traveling within the interchange, the main traffic flow, mostly directed forward, forks to the right for a right turn, and forks to the left, for a left turn, which is out of keeping with accepted norms for an RTH driving system.
It is further noted that, the stated traffic speed with the Buteliauskas road junction is around 70 km/h (43.5 miles per hour) which forces the traffic to slow down from full highway speed (60-65 miles per hour in the US), resulting from the enforcement of circular traffic flow in order to utilize the central area. Further, Buteliauskas road junction offers limited flexibility by disallowing “direct” turns through the interchange central area making the traffic flow more complicated from the road user perspective.
The road user needs to be familiar with the junction system prior to entering and provides no means for correcting driving decisions, such as performing an about turn to return back, if needed.
Additionally, the Buteliauskas road junction does not answer various drawbacks such as high building cost high due to the construction are large requirements, road user possible confusion in a complex road system and provides no flexibility for better adaptation to the ground surface.
Other known existing road junction implementations include also the Stack (Maltezian cross) interchange, the Turbine interchange and the Roundabout interchange, responding only partially to the drawbacks and limitations, as specified hereinabove.
The current disclosure addresses the need to provide an effective, safe and smooth traffic flow for road users, without using traffic signals.